I have been trying to quote the sci-fi short story about the world in which people live in different time streams - some of them are slow, others extremely fast - to the former ones the fast people resemble just a blur, the slow ones seems to be frozen when looked upon by the latter. I want to quote, or at least state the title in my essay and I can't find it anywhere. I read it years ago in Czech translation and somehow remember it was by an English author (it wasn't Aldiss, though.) and that it was quite new (1990s - ).
Previously identified as the answers to People on different time streams and Story-identification, short story with time dilation.
The story starts with people suddenly moving in very slow motion:
I don't think anyone knows exactly when it began. It seemed a fatal disease, at first. Dozens, possibly hundreds, were buried or cremated before the ComaSlow epidemic was recognized for what it was. It was a pseudodeath that struck without warning. There was no precursor, no symptom that gave any clue to its coming.
But then some people start moving so fast they can't be seen:
The new phenomenon began, a month after the onset of the ComaSlow epidemic, with a series of very strange deaths—or rather "disappearances." People simply vanished. Poof.
It turns out that people have started living in different time streams. The rest of the story describes how society adapts to come to terms with this.
At the start of the story, some people seem to just freeze in place, then people start disappearing. Initially there are attempts to care for the frozen people, until it is realized they are aware, conscious and moving, just extremely slowly. (There's a mention of the expressions of terror that their faces take on as they are continually subjected to random manipulations.) The people who disappear initially cause pranks, and some damage until enough people move to the fast streams to form a functioning society. Reservations are set aside for the slow-moving people so they can go about their lives unbothered by the normal-speed (to them fast-speed) people.
The main character (and his eventual wife) take part in an attempt to contact the faster stream, and after being briefly humiliated, delegate constitutional powers to whatever stable governing body is set up there.
At the end of the story they note that they've got a perfect family - he and his wife are still together (never moving far away from one another to not get split) an adult child (who moved to a faster stream, grew up and switched back to their stream) and a perpetually young daughter (who exists in a slower stream and will, for them, never grow up). There's a comment about how his wife insists on combing her hair when they see her, even if she's playing baseball and happens to be sliding into a base when they see her.
The main character also mentions that new faster and slower streams are constantly splitting off, but the fastest people never bother with pranks against people who will never register the effects in their (the fast people's) lifetime.
"Traveler's Rest" by David I. Masson.
Different latitudes on the planet live at different rates. Traveling across them causes one to lose sight of the other latitudes as the time rates are so different that ahead and behind appear only as a blue haze or a red haze.
A few seconds in the warring pole latitudes pass while an entire leisurely lifetime could be lived in the equatorial latitudes. Even people's names lengthen or shorten to adapt to the different paces of life. The protagonist H becomes Had becomes Hadolar becomes Hadolaris becomes Hadolarisondamo, and back again.
At the pole war bunker, the sight-barriers were close in:
Out of the red-black curtain of the forward sight-barrier, which at this distance from the Frontier shut down a mere twenty metres north, came every sort of meteoric horror: fission and fusion explosions, chemical detonations, a super-hail of projectiles of all sizes and basic velocities, sprays of nerve-paralysants and thalamic dopes.
The visible pandemonium was shut in by the sight-barriers’ titanic canyon-walls of black, reaching the slim pale strip of horizon-spanning light at some immense height. The audibility-corridor was vastly wider than that of sight; the many-pitched din, even through left ear in helm, was considerable.
As he travels down the latitudes, there is literally more latitude:
The forward sight-barrier here was hidden by a shoulder of mountain covered in giant lichen, but the southern barrier was evident as a violet-black fog-wall a quarter of a mile off.
And in the lowest latitudes life is easy and relaxed, even though many lifetimes and even evolution proceed at the fastest pace there, during only minutes at the pole:
Holidays were spent either in the deep tropics (where one could gain on the time-exchange) or among the promontories on the southern shores of the North-Eastern Sea (where one had to lose), or, increasingly, in the agricultural stream-scored western uplands, where a wide vista of the world could in many areas be seen and the cloudscapes had full play. Even there the sight-barriers were a mere fogginess near the north and south horizons, backed by a darkness in the sky.
Beyond a limited north-south distance communication is impossible. People communicating over small north-sound distances by radio can hear the distortion in speed of speech. The story refers to time "conceleration".
Unlike the question, people do not see each other as frozen or fast blurs, as they cannot see beyond the sight-barriers, which move along with them as they change latitude.